Question 9
Tom keeps dairy cows but grows no grass, so his cows eat Alex’s grass. For a day when they eat 10 kg of grass, Tom pays Alex 2 litres of milk. For a day when they eat 13 kg, he pays 3 litres. This week they eat 10 kg per day on three days and 13 kg per day on the remaining days. How many litres of milk must Tom pay Alex this week?
